基于有+/-控制D/A转换器的DDFS设计新方法

Novel Approach to the Design of DDFS Based on +/-Controlled D/A Converters

ROM压缩技术已经被广泛地用来减少直接数字频率合成器(DDFSs)的功耗。一个基本的ROM压缩技术是通过使用补码器,利用正弦曲线(0,π)区间上的取样值来恢复(π,2π)区间上的值,但是补码器的使用会增加功耗和面积,而在一贯的设计中,补码器又是必不可少的。本文提出了一个新的DDFS改进设计方法,用一个有+/-控制的D/A转换器来同时实现D/A转换和补码器两者的功能,同时还能减省补码器所需的功耗和面积。

To reduce the power consumption of direct digital frequency synthesizers （DDFS）, the ROM compression techniques are widely used. One of the basic ROM reduction methods is recovering the sampling values in （π,2π） in one period of sinusoid by that in （0,π） performed by a complementor, which increases the power and area cost. This paper presents a new way to design DDFSs by using ＋./- controlled D/A converters, which perform not only the function of a D/A converter but also a complementor, then the power and area cost of a traditional complementor is saved.